Images matter. Whether through a political campaign's choice of symbols, a news headline's metaphors, or a cartoonist's deft exaggeration of a famous face, visual images persist in popular culture and influence public reaction to ideas, people, and, yes, science. Animals have long been used to embody subtle messages — automobile brands chosen to imply speed, or nicknames that capture essential elements of personality — but few animals carry such rich cultural baggage as nonhuman primates. Don't "monkey" around with or make a "monkey" of me! As historian Constance Areson Clark demonstrates in her engaging comparison of cultural and scientific images of evolution, the image choices made by scientists, anti-evolutionists, cartoonists, museum curators, and the press all helped to shape public debate during the 1920s and 1930s and not always in the direction intended.

The book's title might, at first glance, seem just another sensational use of such images, but, in fact, it simultaneously references both a central tract of the anti-evolution debate and the ambiguous personal attitudes of one of evolution's most visible defenders. Alfred Watterson McCann's 1922 book God — or Gorilla attacked paleontologist Henry Fairfield Osborn and challenged the accuracy of the "Hall of the Age of Man" in the American Museum of Natural History that Osborn headed. McCann's publication — one of many salvos in a publicity battle which, Clark points out, raged long before the trial of John T Scopes — targeted a staid and admired museum (a veritable castle of scientific prominence and prestige) and the wealthy and socially connected Osborn, who had been active in the debate against fundamentalists such as McCann, John Roach Straton, and William Jennings Bryan. Osborn was, however, a religious man, an elitist, and a supporter of eugenics. He publicly argued that evolution supported "Christian values" and demonstrated that humankind had always struggled for improvement, physically as well as spiritually, yet he privately expressed distaste for the "image of a simian ancestry." Such ambiguity, Clark points out, characterized the attitudes of many scientists at the time.

Clark skillfully analyzes the technical aspects of the debates (as science's understanding of human evolution was being refined and challenged), but her book holds interest outside the history of science because she also dissects the era's popular culture images of monkeys, chimpanzees, gorillas, and "cavemen" and analyzes strategies chosen or ignored by scientists in their efforts to defend evolution. A "contest among images" played out in the pages of newspapers and magazines, in radio talks, and in museum halls. Everyone — scientists and theologians, evolutionists and antievolutionists — had an agenda; all sought cultural supremacy of their ideas, sought to have their interpretation of life's origins, and of the appropriate delineation of the territory of science and religion, prevail in the public mind. The weapons in that battle continue to be exploited today — satire, ridicule, lampoonery, and photographic comparisons of "man" and "ape." As Clark notes, "the evolution debate was about so much more than the substance of science."

One complicating factor was the increasing complexity of the relevant biology, geology, paleontology, and anthropology. Even though institutions like the nonprofit news agency Science Service were being created to improve public communication, the scientific community's longstanding resistance to popularization for the masses hobbled these efforts. To reach large audiences required using the latest communications techniques like radio, while most scientists remained more comfortable with formats like formal lectures or museum exhibitions. Osborn himself could be dismissive of the very public he claimed to be addressing (he told his publisher that, in writing a popular book, he had "stooped to conquer"). Scientists mindful of the nuances in the evidentiary record would also carefully qualify their statements, while some opponents of evolution simply reduced the choice to one stark question — "God or gorilla?"

Clark offers perceptive analysis of the metaphors, cartoons, and illustrations (including human "pedigrees" and "trees" used in 1920s school biology texts) which peppered the evolution debate, but her book also poses a deeper question. Why did this particular scientific debate capture so much public attention? Certainly, the breakneck speed of technological and social change during the 1920s — automobiles, movies, radio, flappers, jazz — lent credibility to conservatives' anxiety that science disturbed the status quo but, as Clark emphasizes, the two sides also effectively constructed starkly different images of the past. Either human beings stood erect and dignified in the great chain of being, forged in God's image, or else they hunkered on the muddy ground alongside their simian cousins. Neither fundamentalists nor evolutionists seemed willing to compromise in the images they employed in their writings and lectures.

Popular culture then worked its own magic, conflating cute chimpanzees with powerful gorillas and eventually fashioning a satirical version of a brutish, stoop-shouldered, slack-jawed "caveman" (the comic strip Alley Oop, still carried in hundreds of newspapers today, was created in 1932). In her chapter on "Redeeming the Caveman, and the Irreverent Funny Pages," Clark shows how anti-evolutionists exploited science's own visualizations to advantage. Osborn and other scientists may have imagined that they could determine how evolution would be presented to the public, but even powerful institutions like a New York museum could not control how anti-evolutionists would interpret the images in public exhibit halls. McCann frequently turned Osborn's own displays against him. Osborn had worked with curators and designers to "create a vision of cavemen ennobled, rather than degraded," and yet, Clark points out, they added elements (for example, facial and body hair, or rough wooden clubs) which had little scientific basis, and the murals, busts, and dioramas seemingly celebrated a vision of brutal creatures capable of violence. Critics like McCann then easily pointed to such artistic license as proof that the exhibits "represented speculation, not science." Interpretation (and misinterpretation) of images and evidence thus helped, Clark explains, to raise potent questions "about the very definitions of science and its boundaries," a result that served neither science nor the public well. This history offers an important lesson for popularization and public communication of science today.